Angels don't eat--they aren't human.
Seventeen year old Mercy is becoming an angel. She can feel her wings growing--they itch her shoulderblades.
Mercy can't/won't/doesn't eat and her parents decide to send her to an eating disorders institution to help Mercy face her illness.
Mercy and her family aren't like most of the YA characters depicting adolescent worlds. Mercy is highly intelligent, her mother is an extreme activist (environmental lawyer) and does not hide her feminist perspectives from her daughter, and Mercy is a wealth of knowledge and perspective uncommonly fresh and unique.
As I got towards the end I thought it was wrapped up rather too neatly, but then Antieau weaved a totally different storyline into the conclusion, I was just amazed as to how sucked in I was.
I am glad I stuck with it, and even though the book does have some moments of hard-to-believe. The manner in which Mercy finds a way to confront her eating disorder is really original and well-worth the read.